Revenues from Contracts with Customers (Schedule of Total Revenues Broken Out by Revenues from Contracts with Customers and Other Sources of Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenues:
Revenue from contracts with customers	$ 810,892	$ 646,469	$ 2,377,946	$ 1,998,521
Other sources of revenue:
Interest	510,823	505,198	1,515,803	1,439,532
Principal transactions	137,089	114,841	429,677	336,063
Other	17,056	(921)	35,388	(4,927)
Total revenues	1,475,860	1,265,587	4,358,814	3,769,189
Commissions [Member]
Revenues:
Revenue from contracts with customers	183,445	165,075	552,238	499,983
Investment Banking [Member]
Revenues:
Revenue from contracts with customers	243,182	146,887	690,412	525,591
Asset Management [Member]
Revenues:
Revenue from contracts with customers	382,616	333,127	1,130,849	968,960
Other [Member]
Revenues:
Revenue from contracts with customers	$ 1,649	$ 1,380	$ 4,447	$ 3,987